1. Field of the Invention
This invention relates to a method of dry cooling coke and, more specifically, to such dry cooling which includes the crushing of the hot coke to small particles prior to the delivery to a cooling shaft or the like.
2. Description of the Prior Art
The dry cooling of coke is a process which is sometimes employed in contrast to the wet quenching of coke. In wet quenching, the coke is sprayed with water until it has undergone sufficient cooling. Wet quenching, of course, is a simple process, but one which produces considerable emissions. Additionally, the energy contained in the hot coke is lost during some wet quenching operation.
In contrast to wet quenching, dry-cooled coke contains no water, which unnecessarily consumes additional heat when, for example, the coke is used in a blast furnace. As a result of the improved dry cooling process, a higher coke strength and lower abrasion values are achieved.
The basic principle of dry cooling of coke is to directly extract the tangible heat of the coke by means of an inert cooling medium, and to obtain this heat in a readily-usable and efficient form, such as steam. The process typically includes the hot coke being removed from the coking chamber in buckets. The buckets are transported to a vertical cooling shaft and are emptied into the top of the shaft. As the coke is still falling through a sluice or lock onto the shaft containing the coke, it is cooled by a countercurrent or counterflow of inert gas. At the base of the cooling shaft, the cold coke is removed by means of a lock or sluice. The hot circulating gas exits the shaft in the upper portion and is conducted by way of a dust removal apparatus to the waste heat boiler for steam generation. The cooled gas is sucked in by the fan through another dust removal apparatus and is injected in the lower part of the shaft to cool the coke.
A more recent development provides that there is both a direct and indirect heat extraction from the coke by inert gas and by evaporator heating surfaces. The heat extracted in the inert gas circuit is used, on one hand, to heat water as it flows by the evaporator heating surfaces and, on the other hand, to superheat the steam. By means of these measures, the quantity of circulating gas is reduced, and thus the power consumption required to move it is also reduced. The coke heat to be extracted is completely converted into steam.
The determining factor for the efficiency of such installations is primarily the thermal transfer between the coke and the cooling surface and/or between the coke and the inert gas.
U.S. Pat. No. 4,668,343 discloses a method of dry cooling red-hot coke in a vessel having an antechamber with a small discharge leading to a vertically elongated cooling chamber which is of a larger dimension than the discharge and with both the cooling chamber and the antechamber having fluid cooling tubes in one or more walls and the ceiling thereof and also having cooling tube bank diverging downwardly from the discharge of the antechamber into the cooling chamber. The method comprises directing the red-hot coke to be cooled downwardly through the antechamber and into the cooling chamber so as to maintain a charge of coke in the cooling chamber to the conical charge cone of the cooling tubes adjacent the top of the cooling chamber which extends downwardly below the discharge, thereafter circulating a coolant through the cooling tubes to effect transfer of sensible heat from the coke to the fluid and directing a cooling gas from the bottom of the cooling chamber upwardly through the coke and above the entire area of the coke charging cone and then into an exhaust duct to one or more waste heat boilers.
U.S. Pat. No. 4,559,107 discloses a method of dry cooling coke using a coke transporting bucket which has a removable cover with an exhaust pipe extending from the interior of the bucket to an exterior exhaust connection and a cooling shaft for the coke comprises directing red hot coke into the bucket, covering the bucket with the cover and transporting the coke to the cooling shaft and connecting the exhaust pipe to the exhaust system while the bucket is in the shaft and emptying the bucket into the cooling shaft. The coke transporting bucket comprises a container having a bottom discharge which is closable by a flap and a removable cover which seats around the rim of the container to seal it. An exhaust pipe is carried by the cover and it extends into the interior thereof for removing gases from within the bucket and delivering them to an exterior connection which is connectable to an exhaust line. One or two exhaust pipes may be provided on the cover and each includes cover flaps which are biased into a closed position but which open to connect to the exhaust system when the cover is positioned to engage the exhaust line. The cover advantageously includes longitudinal girders which extend outwardly from each side or end of the cover and provide a means for supporting the cover when the bucket is lowered beneath a support structure to free the cover from the bucket.
U.S. Pat. Nos. 4,521,279; 4,556,455; 4,606,793; and 4,701,243 are also directed to and disclose various methods and equipment used to cool coke. All of the above-mentioned patents are incorporated herein by reference as if the entire contents thereof were fully set forth herein.